The present invention relates to a method for preventing multiplication of algae by the use of a silicone emulsion and, more particularly, to a method for preventing multiplication of algae by utilization of a cationic emulsion of a polydiorganosiloxane containing an amino group, an epoxy group and a hydroxyl group as functional groups.
It is well known that algae multiply in an aqueous medium, for example, in a water system, and adhere to and accumulate on the surfaces of solid materials therein. For example, the algae adhere to a fishing net, and the surface of the net is thus contaminated therewith, so that fishing work is disturbed and the durability of the net is remarkably impaired thereby. Further, in a closed system apparatus using an aqueous medium, valves disposed in the pipings are often clogged with algae.
In order to overcome these disadvantages, there have heretofore been suggested some methods for preventing multiplication of the algae. For the protection of the fishing nets used in fishing work, anticontaminating agents are generally used. However, most of the agents for the fishing nets contain, as effective components, organic tin compounds having heavy metals harmful to human beings, and which harmful components tends to get into fish and accumulate therein. Moreover, with regard to the closed system apparatus, it has been suggested and practiced to clean the apparatus with water containing a chlorine gas. This method is effective to inhibit multiplication of the algae, but its applicable fields are limited narrowly since the chlorine gas used in this method is toxic to animate creatures coexistent with the algae, for example, shell and fish, and additionally human beings.
The present inventors have conducted intensive research in order to overcome the problems of the conventional techniques, and as a result, they have found that when the surfaces of the solid materials are coated with an emulsion composition of a polydiorganosiloxane containing a quaternary ammonium salt, the emulsion composition can prevent the algae from adhering to and accumulating on the solid materials. Furthermore, this composition does not have any bad influence on animate creatures such as fish. On the aforesaid knowledge, the present invention has now been completed.